Doctor Mirabilis is a historical novel written in 1964 by the science fiction author James Blish. This is the second book in Blish's quasi-religious trilogy After Such Knowledge, and is a recounting of the English philosopher and Franciscan friar Roger Bacon's life and struggle to develop a 'Universal Science'. Though thoroughly researched, with a host of references, including extensive use of Bacon's own writings, frequently in the original Latin, the book is written in the style of a novel, and Blish himself referred to it as 'fiction' or 'a vision'.